The invention relates to an endoscope fill bar as defined in th preamble of claim 1.
Endoscope are used in minimally invasive surgery and for diagnostic purpose. When used as intended, they are advanced through a body duct, which for that purpose was pierced into the patient""s body, or through a natural duct of that body, and into the body cavity to be investigated. Obviously too, the insertion and advance of the endoscope should be as easy as possible and with a minimum of trauma to the body duct. At least with respect to the insertion, such minimization might be attained by rounding the distal tip of the endoscope. The endoscopes themselves however cannot be rounded permanently because having to meet different other requirements, for instance assuring good observability and illumination of the treatment region, the flow to-and-fro of rinsing fluid, or the insertion of implements.
Accordingly a fill bar is used to round the distal endoscope tip. This fill bar is inserted through a clear endoscope duct into this endoscope. When in its functional position, the fill bar runs through the entire length of the endoscope from which it projects distally by a rounded, distal zone. Once the fill bar is in position, the endoscope is moved into the body duct and advanced as far as the pertinent region of surgery. Thereupon the fill bar may be removed in the proximal direction from the endoscope and treatment may begin.
A fill bar outside the above species furthermore is known from the German patent document 81 19 687 U 1, comprising a lever resting in articulating manner on said bar""s distal end so as to be adjustable at its proximal end. This lever when in its functional position may pivot in front of the distal endoscope end and must match the endoscope cross-sectionally.
When the duct receiving the fill bar being inserted into the endoscope substantially is the full endoscope cross-section, for instance the way it is with an endoscope with a detachable shank through which the fill bar may be guided, then such a fill bar shall satisfactorily round the distal endoscope tip. However there remains a slight offset between the endoscope and the fill bar which, in the above instance, substantially corresponds to the shank""s wall thickness or where applicable to the thickness of the insulating inset constituted at the shank end.
But if this offset is larger, endoscope insertion in spite of the use of a fill bar still may be traumatizing.
A fill bar is known in the state of the art which is fitted with a device allowing varying the cross-section of the zone distally beyond the endoscope in its functional position. Such a fill bar of the species of the present invention illustratively is known as the Leusch expansion shutter (G. Leusch, [A smooth fill bar of beak-free resection shanks], UROLOGE A 13, 274-275-1974). This fill bar comprises two parts which are axially displaceable relative to each other and an annular soft bead in the distal end zone that may be compressed or tensioned by said relative displacement so that an offset as mentioned above between the fill bar and the endoscope may be overlapped. Stretching the bead entails a reduction of its diameter and thereby allows inserting and retracting the fill bar through the endoscope duct.
However even this improved fill bar fails if only an endoscope duct of small insertion cross-section relative to the total endoscope cross-section is available to insert the said fill bar. Such is the case for instance with wide shank implements wherein only one functional duct of substantially lower cross-section than that of the endoscope is free. As regards such implements, the distal endoscope tip heretofore could not be satisfactorily rounded using fill bars. Even the above cited expansion shutter may compensate only slight offsets. Moreover it shall always be unsuitable if the free duct used to insert the fill bar is mounted eccentrically in the endoscope, or when the endoscope itself lacks a circular cross-section. Using the heretofore known fill bars in all these instances may only partly cover, i.e. round off the tip, other bared edges remaining.
Accordingly the objective of the present invention is to create a fill bar overcoming the above described problems but allowing inserting endoscopes exhibiting the said unfavorable tip geometry into a body duct while causing only slight trauma.
This problem is solved by the invention using a fill bar defined by the features of claim 1.
Accordingly, the device to change the cross-section of the region distally projecting beyond the endoscope in the functional position of the fill bar is a pivoting lever supported in that region. By means of an appropriate and proximal adjustment element, said lever may be pivoted within the lever""s pivoting range to enlarge the cross-sectional area of the fill bar. Such pivoting motion also may be reversed by said adjusting element, thus reversing the cross-sectional enlargement, and the fill bar then again may be guided through the free endoscope duct. At its distal end said lever articulates on the fill bar so that, in its pivoted position, the fill-bar cross-section increases from its distal tip and in the proximal direction over the length of this lever.
The fill bar of the invention also allows safely covering, i.e. rounding, even substantial offsets. For that purpose, the length and the pivoting angle of the lever must be selected appropriately. In particular even endoscopes comprising an eccentric fill-bar insertion duct may be reliably rounded because said lever also allows non-circular enlargement of cross-section. At the same time the present invention also is characterized by simple design and simple operability.
The lever must be supported at the fill-bar zone distally projecting beyond the endoscope in such a way that the lever shall be able to assume a state wherein the cross-section has been enlarged due to pivoting the lever and a state allowing passing the fill bar through the free endoscope duct.
Illustratively the lever may articulate on the distal end of the fill bar. However claim 2 advantageously proposes that the lever shall be mounted proximally from a distal, rounded tip of the fill bar. This distal fill-bar tip then retains unchanged its selected, closed, traumatic shape even when the lever has been pivoted, and in this manner it improves insertion of an endoscope fitted with this fill bar.
The lever geometry may be selected in arbitrary manner. However in a preferred embodiment defined in claim 3, this lever preferably shall comprise a cylindrically convex outside surface away from the fill bar because said surface shall come into contact with the body-duct tissue when the fill-bar fitted endoscope shall be inserted. Said convex cylindrical shall advantageously reduce the trauma of insertion.
Claim 4 advantageously proposes that the free lever end be designed to enable resting on the distal endoscope end. As a result the pivoted lever shall be stabilized at insertion, and gaps between the lever and the endoscope tip shall be avoided. Stability of the pivoted lever is important because significant forces are applied to said lever when the endoscope is inserted into the body duct which usually must be expanded.
In addition, or as an alternative in the event of a stable design to the step of claim 4, an affixation mechanism may be used to keep the lever in its pivoted position. Preferably as regards claim 5, the affixation mechanism shall be mounted on the adjustment system because latter can be reached outside the endoscope by the surgeon and hence the affixation mechanism shall be more easily actuated. In a simple design, such an affixation mechanism might be for instance a detachable clamping screw or a lock so that the adjustment system shall be locked. However an arbitrary detent mechanism also may be used, for instance a spring-loaded ball which upon actuation of the adjustment system shall engage corresponding grooves. The affixation mechanism shall be designed in such a way that the forces acting on the pivoted lever shall be opposed.
Moreover a spring element may be configured between the lever and the fill bar in order to facilitate pivoting the lever on one hand and on the other hand to apply a retention force on the pivoted lever to oppose the forces exerted on the lever during insertion. Said spring force shall be selected in such a way that folding the lever shall still be possible with moderate force.
Moreover the lever and the associated adjustment system besides the adjustment link may be designed in such a way that the lever may assume several pivoted positions, that is several pivot angles. Such a state on one hand might be reached by stepwise adjustments, but on the other hand it might also be carried out in continuous manner. In both cases the fill bar shall be appropriate for various sizes of offsets, also for endoscopes of various diameters.
The fill bar advantageously shall be designed so that it might reach its functional position only in one predetermined rotational position relative to its endoscope in order that the pivoting direction of the lever always shall correspond to the direction of the offset to be covered between the fill bar and the endoscope. In addition the fill bar and the endoscope shall be coupled in mutually irrotational manner in order that the fill bar shall be precluded from rotating relative to the endoscope, whereby the lever no longer would overlap optimally. This feature is especially significant for an insertion duct which is eccentric in the endoscope or with respect to an endoscope of oval cross-section.
Claim 6 advantageously proposes mounting several levers which may be pivoted in different directions. These arms then may overlap offsets in several directions in the manner of the spokes of an umbrella.
Advantageously in the above and as stated in claim 7, levers of different lengths are used. In this manner small offsets for instance may be covered in one direction with short arms and large offsets in another direction with commensurately longer arms. As regards endoscopes exhibiting oval cross-sections, the end face to be covered is not configured symmetrically with respect to the center about the insertion duct, and accordingly the above suggested length differentials of the levers result in improved overlap or rounding.
The adjustment system is advantageously designed in the manner defined in claim 8 in that, upon lever motion due to actuating the adjustment link, the free lever end essentially moves along a straight path transversely to the longitudinal axis of the fill bar. This goal may be attained by supporting the lever on a displaceable shaft. Short of such a design of the adjustment link, the pivoting motion of the lever would require a short tensive motion in the proximal direction at the fill bar in order to move the pivoted lever to rest against the distal endoscope tip or a short distal motion of the fill bar, before it would be possible to retract the lever by means of the adjustment link.